In many devices in the field of control engineering, e.g. regulators, actuators and sensors for proportional control, output values, i.e. desired values and actual values for e.g. valve positions and temperatures, are generally represented by the voltage of an analogue signal that can range between e.g. 0 and 10 volts. In many other devices receiving these analogue signals, these values are expected to be in the form of a current signal, e.g. 0 to 20 mA.
This constitutes a problem, as not all devices will interact, when the output of one device does not correspond to the expected input of another device. In certain devices the mode of operation, i.e. current control or voltage control, can be switched by means of a jumper, e.g., but this switch means one more installation step and it can also lead to an incorrect installation. Also, two separate solutions, one for current control and one for voltage control, lead to a higher cost for electronic circuitry.